Method for texturing yarns



L. N. BACKER METHOD FOR TEXTURING YARNS Nov. 26, 1968 2 Sheets-Shet 1 Filed May 51, 1966 Nov. 26, 1968 L. N. BACKER METHOD FOR TEXTURING YARNS 2 Sheets-Sheet 2 Filed May 31, 1966 United States Patent 3,412,443 METHOD FOR TEXTURING YARNS Leonard N. Backer, Westport, Conn., assignor to Fabric Research Laboratories, Inc., Dedham, Mass., a corporation of Massachusetts Filed May 31, 1966, Ser. No. 554,084 6 Claims. (Cl. 28--72) ABSTRACT OF THE DISCLOSURE Monoand multi-filament yarn is continuously textured by running the yarn linearly into and out of head-on engagement with a surface angularly intersecting its projected path of travel continuously to bend the yarn beyond its elastic limit at the temperature of operation and running the yarn away from the bending operation in a freely suspended and in an untaut relaxed state which prevails until the yarn has cooled so as to maximize retention of coil configurations imparted by the bending, thereafter straightening the yarn to at least partially uncoil the yarn and collecting the straightened yarn.

This invention relates to textured yarns and more particularly to an improved method for the production of textured yarns of coiled, coil-like or otherwise shortened configuration formed particularly from thermoplastic synthetic continuous monoand multi-filament yarns and to the resultant product.

The utility of textured yarns, particularly in the garment industry, has resulted in the development of a variety of commercial yarn texturing processes which have individual advantages or drawbacks dictating the choice of process according to the particular characteristics desired in a given fabric and often depending upon Whether the fabric is knit or woven.

Of the known processes, what has become known as edge crimping produces a yarn which has the favorable characteristic of being torque-free--a valuable asset in knitting on seamless knitting machines. Its method of production, however, has certain disadvantages from an operational standpoint as hereinafter discussed. Moreover where bulk is desired, controlled thermoshrinkage is a necessary afterstep to the edge crimping process.

One object of this invention is the production of torquefree textured synthetic yarn by a novel method.

Another object of the invention is the provision of such a method which is simplified by reason of elimination of at least one troublesome variable inherent in present-day edge-crimping methodsnamely, yarn tautness on the output side of the crimping edge.

Another object of the invention is the production of a balanced torque-free multi-filament textured yarn which can be bulked solely by stretching and thereafter relaxing the yarn.

Another object of the invention is the production of a torque-free synthetic bulk yarn without the necessary application of heat over and above that generated by the passage of the yarn through the processing apparatus.

Another object of the invention is the production of a textured yarn which, incidental to the texturing operation, can attain a material increase in denier without undue loss of tenacity, thereby producing a textured yarn having better opacity and cover than the parent yarn.

Yarn, in accordance with this invention, is fed by means in surface frictional engagement therewith, at a constant rate linearly towards a surface which intersects the pro- A significant feature of this invention is that the yarn emerges at the point of its separation from engagement with the intersecting surface without being under any externally-induced drawing tension and under no stress other than the internal stresses imparted by the flexing and bending operation, a condition which is hereinafter referred to as tautless or untaut.

When yarn is thus bent it is subjected to compression forces on its inner side and extension forces on its outer side which causes the yarn to coil. In accordance with this invention, these forces are created by pushing the yarn into engagement with a bending surface which can be likened to a female die, rather than by pulling, as in edge crimping, the yarn over a blade edge, which may be likened to a male die. The result is, when the yarn is bent beyond its elastic limit at the temperature of operation, that the yarn relaxes into a fully developed coil-like configuration as it emerges untaut from engagement with the die surface and can be and is maintained freely suspended and substantially tautless until it has cooled. Thermoshrinkage causing a material increase in denier can occur while the yarn is in the tautless state depending upon the temperature of operation. Even after cooling, only that negligible tension is applied which is incidental to the collection of the yarn, as in a package, i.e. sufficient to straighten and at least partially uncoil but not stretch. Such a straightening operation serves, in the case of multifilarnent yarn, to dephase the coils and produce a bulked yarn providing excellent cover.

The outgoing yarn is no longer affected by being the instru mentality, as in edge crimping, for transmitting the bending forces to the crimping edge. The elimination of outgoing tautness as an operating factor wholly removes it as a variable that needs to be taken into account in setting up or maintaining a given operation. Breakage by reason of undue outgoing tension is wholly eliminated. Additionally one wholly avoids other undesirable consequences of taut yarn outgo which include the disadvantages of subjecting the yarn while it is still at elevated temperature and before it cools to forces tending to redraw the yarn, not only destroying stresses set up by the bending operation, but also preventing thermoshrink denier increase which might otherwise occur.

When practicing the methods of this invention, the die surfaces are preferably formed by distorting a running elastic surface to create a depression through which a yarn can be run, utilizing the running surface in advance of the depression as the sole yarn driving means.

While, in the case of edge crimping, with outgoing yarn tautness imposed by drawing tension, the art has been led to believe that acute bends are preferred, if not imperative, it has been found that in tautness output crimpingor coiling of this invention, the opposite holds true. In the absence of withdrawal tension, yarn cannot be run through acute angles, e.g. those created at the bottom of a depression extending substantially normal to the plane of advance of a running surface. Obtuse angles, which have been criticized as failing to impart satisfactory crimp in case of taut output edge crimping, are most satisfactory for tautless output texturing in accordance with this invention. The use of less acute angles without loss in texturing is desirable as there is less cross-sectional distortion.

Accordingly, the depression is preferably formed by two merging surfaces forming an included obtuse angle and with one wall of the surface much longer than the intersecting surface.

Such a depress-ion may be readily formed in an elastic running surface by a depressor blade, which is held, in the case of the elastic surface being a roll, against the revolving roll surface with the main engaging surface of the blade at an acute angle to the tangent to the path of normal revolution of the roll at the radius passing through the edge of the blade. The blade thus acts as a detrusor to thrust the yarn downwardly into the depression as it runs and upwardly out of the depression as the yarn proceeds between the end edge of the blade and the leading wall of the depression formed in the roll. Under typical operating conditions, this downward and outward detrusion produces a rooster tail discharge of the yarn out of the depression beyond the blade edge.

While various forms of apparatus may be used to practice the invention, a preferred form of apparatus is shown in the accompanying drawings, being in a specific form which is not my invention, but is the subsequent invention of another as claimed in co-pending application Ser. No. 554,085 filed simultaneously herewith.

FIG. 1 is a schematic elevational view showing such apparatus;

FIG. 2 is an enlarged perspective view of a portion of the apparatus shown in FIG. 1;

FIG. 3 is an enlarged, detailed cross-sectional view of the apparatus shown in FIG. 2;

FIG. 4 is an enlarged elevational view, partly in cross section, of certain portions of the apparatus;

FIG. 5 is a fragmentary cross-sectional view taken along the line 55 of FIG. 4;

FIG. 6 is a fragmentary cross-sectional view taken along the line 66 of FIG. 4;

The primary elements of the apparatus comprise a rotatable roll 10, which has a deformable elastic surface which, at one point, is depressed on account of its pressure engagement with a smooth, flat surface 12, of an incompressible element or blade 4 which terminates in a transverse straight edge 18, preferably formed in a carbide blade tip. The back or outside of the blade shown in FIG. 3 is bevelled back at a 45 angle, though it may be square or at some other angle less than 90. The blade 14 is held in a blade holder 20 (FIG. 4) by screws 22'. Blade holder 20 is mounted in a cage 24 for reciprocal adjustable longitudinal movement relative thereto, for which purpose the inner end of blade holder 20 is conrected to a rod 26 which is screw-threaded through a head 28, fixed at the upper end of cage 24.

Cage 24 has attached to its rear surface a cylindrical block 30 which is seated in a bearing 34 formed in an arm 36 which in turn has a circular bearing 38 surroundjustment, to change what is hereinafter referred to as the blade angle, i.e. the angle which the inner blade surface 12 makes with a tangent to the path of rotation of the periphery of roll 10 at the pivot axis of arm 36, and thus change the geometry of the depression for various operations. As shown in FIG. 3, normally the depression has a long fiat infeed surface merging into a short abruptly rising surface forming an included angle greater than 90.

When the blade 14 is pressed against the roll 10 a depression of controlled contour is formed in the surfaces of the roll, then as the parent filament yarn is fed between the blade and rotating roll, the yarn is bent outwardly as it conforms to the contour of the depression beyond the end of the blade, inducing strains in the yarn which cause the yarn to assume a coiled configuration as is emerges freely suspended and untaut from the bending operation. The interaction of the roll surface, blade and yarn can heat the yarn to a temperature high enough to soften the yarn. With many synthetics, including nylon, polyproylene, polyethylene, cellulose acetate, etc., the softened deformed yarn upon rapid cooling in its untaut state attains a permanent set.

FIG. 1 shows diagrammatically how a yarn is run through the machine, including a source of untextured yarn at 58, an input gate 64 and a series of pins 66 leading to a take-up roll 68. The yarn free falls from the blade freely suspended and untaut as shown at 67 and the free fall should not be so great that the weight of the falling yarn has any detrimental effect upon formation of coils of the desired tightness. The pins 66 serve to straighten and at least partially uncoil but not stretch the yarn filament or filaments after the yarn has cooled during its free fall, for collection in a tubular package on roll 68. They also serve, in the case of multi-filament yarn, to dephase the coils.

A suitable constant speed drive is provided for roll 10. Also, if required, a static eliminator of commercially l nown construction may be placed to act on the free fallmg yarn.

The following examples are given as illustrative of operation in accordance with the invention and wherein the roll 10 was operated at a peripheral speed of 250 linear feet per minute. The roll had a surface roll hardness of 83 in Shore Durometer units and the roll diameter was 3-15/16 inches.

Multi-Filament Mono- Filament Polyanude Cellulose Polyester Polypro- Polyamide Nylon 66 Acetate (Dacron) pylene Nylon 6 Yarn Denier 70 70 0 No. of Filaments- 34 20 I34 Yarn Twist 6 0 0 Blade Angle (degrees). 15 15 15 10 Blade Pressure (lbs.).. 5. 7. 21 5. 66 5. 50 5. 625 Blade Position (ems) 1. 6 1. 6 2. 1 1. 9 2.0 Blade Temperature F.) 240 230 200 225 220 ing a cylindrical boss which extends forwardly from the frame of the machine.

Arm 36 is split at 42 (FIG. 4) and provided with a screw 44 so that arm 36 may be adjustably clamped in a variety of angular positions with respect to the frame as indicated by the scale 52 fixed on frame 50.

It is to be noted that the center of the boss 40 lies on the path of rotation of the periphery of the roll 10 so that, when the straight edge 18 of blade 14 is adjusted in its blade holder 20 to lie along the same axis, it will just bear against the periphery of the rotating roll.

In order to press the blade 14 against the roll 10, the upper end of the blade cage 24 is attached to a spring connected to a set screw 62 screw-threaded through a flange 64 extending outwardly from the arm 36 so that the pressure supplied by the springmay be adjusted.

The apparatus thus permits one, by reason of clamp ad- The blade angle referred to in the above table was the angle which the surface 12 of blade .14 made with the tangent to the roll 10 at the point of contact of the blade edge 18 with the surface of the roll for application of pressure. The blade position refers to the distance below the horizontal diameter of the roll at which the blade edge 18 contacts the periphery of the roll before application of pressure. The temperature was measured on the outside of the blade as close to the edge as it was possible to locate the sensitive portion of the temperature sensing instrument.

The multi-filament polyamide yarn referred to in the first column of Table 1 cut from the apparatus before it reached pins 66 had the entangled coils produced by the operation; while the same yarn unwound from takeup roll 68 after straightening and at least partially uncoiling the yarn during its passage through pins 66 was partly disentangled (dephased) and bulked.

Lengths of the yarn show periodic reversals in pitch of the coils providing a torque-free yarn.

Similar results were secured with the other multifilament yarns except that the polyester when straightened did not retain its texture under the conditions used.

The mono-filament likewise coiled with periodic reversals in pitch and the coils drew together to shorten the filament with a permanent set after being straightened and at least partially uncoiled and then relaxed.

Heat self-generated during operation of the apparatus was sufiicient to secure permanent sets in .all the yarns of the table except polyester, and provided increased denier as high as -20%, in the case of thermoshrinkable yarns such as nylon, polypropylene and polyethylene, without diminishing tenacity below 66% of the original grams per denier (4.8 grams per denier in the case of 6 grams per denier untextured nylon yarn). Higher temperature either self-generated or produced by pre-heating the yarn at the input to the roll by running it through a tube subjected to radiant heat at, foi example up to 603 F. tube temperature in the case of thermoshrinkable yarns, can insure maximum diameter increase due to shrinkable but only with increasing loss in tenacity. The beauty of the operation is that, there being no output tautness before cooling, temperatures of operation need not be limited to those which will permit the yarn to withstand output tension without losing texture. On the contrary, the temperatures may be independently adjusted upwardly into ranges which will produce not only maximum denier increase but also more uniform texturing or greater opacity without losing the desired degree of texturing.

What is claimed is:

1. A continuous textile texturing method comprising linearly running a synthetic thermoplastic yarn continuously at a constant rate and elevated temperature into and out of head-on engagement with a surface angularly intersecting its projected path of travel to run said yarn continuously through an arcuate pathway bending in one direction thereby uniformly bending said yarn along its entire length in said direction beyond its elastic limit at the temperature of operation and running said yarn away from said bending operation in a freely suspended and in an untaut relaxed condition permitting strains induced by said bending to cause said yarn to assume a coil-like configuration and cooling said yarn while maintaining said yarn substantially in its untaut relaxed condition, thereafter straightening said yarn to at least partially uncoil said yarn and collecting said straightened yarn.

2. A method as claimed in claim 1, wherein said yarn temperature causes the yarn to shrink, before it 00015,.

to assume filamentary increase in diameter in addition to said coil-like configuration.

3. A method as claimed in claim 1 wherein the yarn is a multi-filament yarn and wherein the bending of the yarn forms entangled coils therein and wherein, after the yarn is cooled, said step of straightening the yarn at least partially disentangles the coils in said multi-filament yarn.

4. A method as claimed in claim 1, wherein said surface intersects said path of yarn travel at an angle greater than 5. The method as claimed in claim 1, wherein the intersecting surface is the surface of a short rising outgoing Wall of a depression formed by a blade in a resilient moving surface, the ingoing wall of said depression providing a relatively longer flat surface of said depression merging into the surface of the outgoing wall, said ingoing and outgoing surfaces having an included angle greater than 90.

6. A continuous textile texturing method comprising linearly running a synthetic thermoplastic yarn continuously at a constant rate and elevated temperature into and out of head-on engagement with a surface angularly intersecting its projected path of travel to run said yarn continuously through an arcuate pathway bending in one direction thereby uniformly bending said yarn along its entire length in said direction beyond its elastic limit at the temperature of operation and running said yarn away from said bending operation in a freely suspended and in an untaut relaxed condition permitting strains induced by said bending to cause said yarn to assume a coil-like configuration and cooling said yarn while maintaining said yarn substantially in its untaut relaxed condition, said intersecting surface being the surface of a short rising outgoing wall of a depression formed by a blade in a resilient moving surface, the ingoing wall of said depression providing a relatively longer flat surface of said depression merging into the surface of the outgoing wall, said ingoing and outgoing surfaces having an included angle greater than 90.

References Cited UNITED STATES PATENTS 2,115,313 4/1938 Matthew et al. 3,028,653 4/ 1962 Evans. 3,028,654 4/ 1962 Evans. 3,102,322 9/ 1963 Whitaker. 3,260,778 7/ 1966 Walton.

FOREIGN PATENTS 883,141 11/1961 Great Britain.

ROBERT R. MACKEY, Primary Examiner. 

